This invention relates to magnetic tape transports, and particularly to tape transducing apparatus therefor.
Various so-called "female" guides have been used in the art to cause the tape to cup snugly around a transversely-scanning rotating head drum. Usually such guides provide solid backing for the tape directly in the plane of the rotating head drum or very close to it, so that an air bearing between the drum and tape would be impossible to form. Usually, also, the drum is shaped to a circumferential V-shaped with the point of the "V" confronting the tape, likewise rendering impossible the formation of an air bearing; and the heads themselves usually project radially away from the drum for many multiples of the maximum thickness of any air bearing that could be formed, at the controlling parameters that are usually feasible for magnetic tape transports in the present state of the art (these parameters being tape tension and speed, and the rotational speed and curvature of the head drum); consequently, even if an air bearing film could be formed, the heads would lift the tape so far above the film that the film would be vented and destroyed.
Of course, in these examples of the art, it may be said that an air bearing was neither contemplated nor desired, and that the desirable object of avoiding frictional contact between tape and drum is achieved by other means. However, the guiding apparatus of these prior art devices has been found to be far more complex to manufacture and to operate, and subject to more precise constraints in operation, than the simple air bearing of the present invention, and its also very simple tape guiding means.
Accordingly, it is an object of the present invention to provide a fluid bearing between a magnetic tape and a transversely rotating head drum.